The present invention relates generally to an ink jet printing device with a plurality of nozzles and more particularly a nozzle position deviation compensation device capable of simple compensation of the positional deviations of the nozzles.
In general, in the case of printing letters or symbols with a plurality of ink dots by means of an ink jet printing device with a head having a plurality of nozzles, one ink chamber and one ink pressurizing device must be provided for each nozzle, so that it is impossible to dispose the nozzles in contact with each other within a width corresponding to that of a single character. As a result, in order to attain effects equal to those obtainable with a device wherein the nozzles are in contact with each other, there has been proposed a head wherein a number of n nozzles are spaced apart in the direction of transport of recording paper by a distance corresponding to m ink dots, which is required for surrounding each nozzle and also are spaced apart perpendicular to the recording paper by a distance equal to the diameter of the nozzle. However, when a dot is recorded with ink discharged from the leading nozzle with respect to the direction of transport of recording paper and then a dot is recorded immediately beside the former dot, ink must be discharged when the next nozzle comes to the position immediately beside the first dot so that there results a time difference between the ink discharge by the first nozzle and that by the second nozzle. Furthermore the ink discharges by the third, fourth, fifth . . . nozzles are deviated in time.
In order to cause the required time deviation in ink discharge, a nozzle distance compensation device may be provided whereby the distance between the nozzles may be compensated by delaying the dot position signal, which is generated by a character generator, in response to a clock pulse from a shift register. With this device, however, the number of stages of the shift register increases with increase of the number of nozzles as indicated below.
______________________________________ Number of Stages of Number of Nozzles a Shift Register ______________________________________ 1 0 2 21 3 42 4 63 5 84 6 105 7 126 ______________________________________
As a result, when constructed with general integrated circuits, the number of elements is increased with a resulting increase in cost.